This is a brief and basic article, but the idea behind it, that we need to stop distinguishing between biological and social (especially as causes in dysfunctional behavior), is spot on - and I really like the term they mention, “neuropsychosocial.”

Why ‘Nature Versus Nurture’ Often Doesn’t Matter

By Michael White • August 22, 2014


(Photo: abstract/Shutterstock)
Sometimes it just doesn’t make any sense to try to separate the social and the biological.
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Every Friday this month we’re taking a look at the relationship between the social and the biological—specifically, how and why the former becomes the latter. Check back next week for the final installment.

When it comes to understanding ourselves, we tend to be splitters: mind and body, nature and nurture, or genes and environment. We take such a split for granted when we ask how the social becomes biological, but sometimes it’s not so useful to dichotomize the world into society and biology. Instead of looking for distinct social and biological influences (and believing that we can change one but not the other), we should recognize that the factors that drive our social behavior can, like a Zen koan, be two things at once.

Take the case of teen alcohol abuse. In a study published last week, an international team of researchers reported the “neuropsychosocial” factors that identify teens who are likely to abuse alcohol. The word “neuropsychosocial” does away with the common nature/nurture divide, and so did the researchers. Rather than asking whether teens abuse alcohol because of social influences or innate biology, the scientists looked at those variables that could be measured, regardless of whether the variables were social, biological, or a mix of both.

The study is part of a long-term European project called IMAGEN, established to understand the “biological and environmental factors that might have an influence on mental health in teenagers.” The project enrolled 2,000 14-year-olds, from whom were collected several types of data, including personal histories, psychological assessments of behavior, brain images, and genetic data. The researchers asked theses teens about their alcohol consumption at the beginning of the study, and then again at age 16. Armed with this data and a relatively large sample size, the scientists set out to answer the question: What neuropsychosocial factors identify teens who abuse alcohol?

In one analysis, the researchers looked for the factors that identified “current” drinkers, 14-year-olds who were already abusing alcohol when the study data were collected. They compared “binge drinkers” (defined as having been drunk at least three times by age 14) to non-drinkers (teens who drank no more than twice before age 16). In a second analysis, they attempted to identify future alcohol abusers—teens who were not drinking at age 14, but went on to get drunk multiple times by age 16. For each of these analyses, they built a computer model that used the measured neuropsychosocial variables to classify teens as drinkers or non-drinkers. The first model correctly identified 82 percent of current binge-drinking teens and 89 percent of non-drinking teens. The second model, predicting future drinkers, didn’t fare quite as well: 66 percent of drinkers and 73 percent of non-drinkers were correctly classified.

The most important identifying factors of current and future alcohol abusers were an inseparable mix of the social and the biological. A look at those factors shows how teasing out distinct social and biological causes would be an analytical nightmare: the different genetic, neurological, and life history variables are linked together in a thicket of feedback connections. For example, a history of romantic or sexual relationships strongly predicted current and future binge drinking behavior. But teen sexual behavior is surely influenced by other variables the researchers measured, like personality (which has a substantial genetic component), and “reward anticipation” or “emotional reactivity,” which were measured using brain imaging. It’s important to keep in mind that the study was not designed to discover which factors cause teen drinking, a much more difficult task. Instead, the researchers focused on what they could measure—an approach that, while it has its limits, is one of science’s most successful strategies.

What are the neuropsychosocial factors that best identify current and future teen drinkers? Some predictive traits include the volume and activity level of certain brain areas: “Future binge drinkers had reduced grey matter volume but increased activity when receiving a reward in the superior frontal gyrus compared to controls.” A personality trait characterized by “searching for, and feeling rewarded by, novel experiences” predicts both current and future teen drinkers. Other factors, like disruptive family events and more developed pubertal status identify current (but not future) drinkers, while “anxiety sensitivity” predicts only future drinkers. Notably, one set of factors that are not very predictive are specific genetic variants associated with alcohol dependence. This isn’t surprising because the individual effect of any one gene on a behavior like alcohol abuse is likely to be small.

With these results, we can we say about the biological basis for the social phenomenon of teen alcohol abuse? Not much more than, “it’s complicated.” And anyway, framing the question like this is a mistake.

We often approach a social problem by splitting it into its social and biological root causes, and assuming that we can change the social ones while working around the supposedly irreversible biological ones. But when it comes to human behavior, this is often not very useful or informative. As the authors write, their data “speak to the multiple causal factors for alcohol misuse,” and, in fact, any one variable, taken in isolation, had a small influence in their study. The predictive power of their computer model came from combining variables that were measurable—regardless of whether they could be neatly categorized as social or biological—into a single risk profile. This profile offers clues for how to find and help at-risk teens, and the most effective interventions may turn out to have little to do with directly treating some key social or biological cause of alcohol abuse. As we think about the connection between our social behavior and our biology, we should, like good scientists, be pragmatic, and abandon the distinction between society and biology when it’s not useful.



Michael White is a systems biologist at the Department of Genetics and the Center for Genome Sciences and Systems Biology at the Washington University School of Medicine in St. Louis, where he studies how DNA encodes information for gene regulation. He co-founded the online science pub The Finch and Pea. Follow him on Twitter @genologos.

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Michael White - How and Why Does the Social Become Biological?

This is a cool article from Pacific Standard. While this article focuses on math and reading, one of the clearest examples of the social becoming biological is attachment theory, which explains how relational experience becomes encoded in brain architecture and function.

How and Why Does the Social Become Biological?

By Michael White • August 01, 2014

(Photo: Syda Productions/Shutterstock)

To get closer to an answer, it’s helpful to look at two things we’ve taught ourselves over time: reading and math.
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Every Friday this month we’ll be taking a look at the relationship between the social and the biological—specifically, how and why the former becomes the latter. Check back each week for a new installment.

It’s one of the most irresistible and controversial questions in science: “How and why does the social become biological?” The classic mind-body split is something we feel intuitively, a distinction between our “biology”—our anatomy or our physical health—and our social, decision-making minds. So it can be jarring to hear claims like this: “People differ in their intelligence, personality, and behavior, and a century of research in behavioral genetics leaves little doubt that some of this variation is caused by differences in their genomes.” No matter where we look, we always find the influence of genetics—the social is never entirely free of the biological. But what does it really mean to say that social or mental traits are influenced by genes?

Consider two traits that didn’t evolve “naturally,” but rather were completely invented by humans: the ability to read and do mathematics. Last month, a consortium of scientists sponsored by the Wellcome Trust published a study showing that “the correlation between reading and mathematics ability at age twelve has a substantial genetic component.” In other words, reading and math abilities aren’t merely the result of a decision to work hard at them, or an opportunity to learn; they also depend on DNA.

In one sense, this is trivially obvious. The reason that children learn to read and chimpanzees don’t has nothing to do with the chimps’ lack of educational opportunities; it’s entirely genetic. The physical nature of our brains allows us to develop mental skills that are hopelessly out of reach for other animals.

But when we say a mental trait is influenced by genetics, we clearly mean more than that; we’re also making a statement about the role of genetic differences among people. Learning to read and do math involves some very complex brain biology. New links are made between different specialized areas of the brain, and old parts are re-purposed to engage in something that human brains didn’t do until relatively recently. All of this brain rewiring depends intimately on the chemistry of our neural cells, chemistry that is subtly altered by thousands of genetic differences that change the properties of the molecules involved. Unlike the precision engineering that goes into the latest Intel chip, the human brain’s process tolerances are rather wide—nearly all of our molecular parts show some variation among the human population.

Genetic variation is an unavoidable and central fact of biology, and it is at the heart of the relationship between the social and the biological. There never was a master copy of the human genome; species nearly always exist as populations of genetically varied individuals. These genetic distinctions affect every chemical process in our cells, and because absolutely nothing we do happens without some cell chemistry, everything about us is potentially influenced by genetic variation.

The Wellcome Trust researchers studied the influence of genetic variation on math and reading skills, and the correlation between them. Using data collected from nearly 3,000 sets of twins who had taken standard reading and math tests, they used two methods to examine the role of genetics.

In the first method, they searched directly for an association between a specific DNA difference and scores on tests for math or reading. The idea behind this is fairly simple: Consider a place in the human genome where people differ—some people may have the chemical letter “A,” while others have “G.” Do people with an “A” have, on average, higher test scores than those with a “G?” You repeat this test for thousands or millions of different places in the genome and find the DNA differences with the strongest association. In practice, scientists don’t merely compare the averages of “A” versus “G”; they use a more powerful statistical procedure, but the point is the same: to find specific genetic variants that correlate with differences in test scores.

The second approach, using the resemblance between twins, is more indirect—it doesn’t involve knowing any of the actual DNA differences involved. Since twins share a common family environment, but identical twins are closer genetically than fraternal twins, it’s possible to quantify the genetic and environmental influences on a trait without saying specifically what those influences are.

From these analyses, the researchers came away with three big results that nicely illustrate what it means to say that a behavioral or mental trait has a genetic component. First, the twin analysis showed that genetics explains many of the differences in reading and math test scores in the studied population. But the researchers were unable to find any reproducible association between any specific DNA difference and reading and math ability, suggesting that the total genetic effect is the cumulative result of small changes in many different genes. And finally, they found that not only were reading and math scores influenced by genetics, but also that the correlation between reading and math scores showed a strong genetic influence, suggesting that these skills are influenced by “generalist genes.”

What is a “generalist gene”? The idea, proposed years ago by Robert Plomin, one of the study authors, and Yulia Kovas, is that many of the genes involved in cognitive processes don’t have highly specialized roles limited to one part of the brain. Instead, each generalist gene influences many different brain processes, and conversely, each brain process is the combined result of many different genes. Hence, common genetic variation in any one gene will have only a small effect, but on many different traits at the same time.

Importantly, genetic studies like this one also say something about the importance of the environment. The authors argue that “our results highlight the potential role of the learning environment in contributing to differences in a child’s cognitive abilities at age twelve.” They’re suggesting that when a child’s reading and math abilities—which should be correlated—diverge from each other, there is an opportunity to make a productive change in the learning environment.

Genetic variation influences every cellular process, and everything we do depends in some way on the processes in our cells; ultimately, the social and the biological are inseparable.

~ Michael White is a systems biologist at the Department of Genetics and the Center for Genome Sciences and Systems Biology at the Washington University School of Medicine in St. Louis, where he studies how DNA encodes information for gene regulation. He co-founded the online science pub The Finch and Pea. Follow him on Twitter @genologos.

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